At present, in the conventional manufacturing process of low temperature poly-silicon thin film transistor (LTPS-TFT), a contact hole configured to connect the source/drain (SD) and low temperature poly-silicon may be fabricated by a dry etching process. The dry etching gas generally uses CF4 or SF6, but the selectivity of the two gases to poly-silicon (Poly-Si) is not good, but an etch rate of the two gases to Poly-Si is relatively large, easily leading to greater loss of Poly-Si and affecting the ohmic contact between SD and Poly-Si, thereby affecting the electrical properties of the thin film transistor and even leading to the phenomenon of current crowded. Liquid crystal displays are widely applied due to numerous advantages such as thin bodies, energy saving, radiation-free, etc. Most liquid crystal displays available on the market are backlight-type liquid crystal displays, and such liquid crystal display includes a liquid crystal panel and a backlight module. The working principle of the liquid crystal panel is placing liquid crystal molecules between two parallel glass substrates and loading a driving voltage on the two glass substrates to control rotation directions of the liquid crystal molecules, for refracting rays of the backlight module to generate images.